A compact portable electronic apparatus or portable electronic terminal such as a smart, phone or a wristwatch type terminal uses a thin, pouch-type battery as a power source.
The thin pouch-type battery has a configuration in which an electrode group including sheet-like positive and negative electrodes and a separator is enveloped between two laminate films, each of which is made of a metal foil or a resin layer having a thickness of about 0.1 mm, and a liquid, gel, or solid electrolyte is injected therein. For the laminate film, a material, which prevents the electrolyte therein from leaking out in a case where the battery is deformed and damaged from an impact or the like due to an external force, in a case of deterioration due to the service life of the laminate film or a temperature, change, or the like, is selected.
Recently, many electronic apparatuses are worn directly on a human body, and for example, some apparatuses are curved, in advance so as to be fitted to a wrist. Therefore, the battery needs to be also curved so as to be fitted to the shape. Accordingly, there is a demand for a thinner and further flexible battery as such a battery.
A thin pouch-type battery in the related art has a wave section formed on the entire laminate film, which has durability but does not have good elasticity, thereby configured to enhance flexibility of the entire laminate film for example, see Japanese Patent Unexamined Publication No. 2000-173559).
FIG. 14 is a view illustrating a thin pouch-type battery in the related art disclosed in Japanese Patent Unexamined Publication No. 2000-173559.
As illustrated in FIG. 14, laminate film 201 disposed on the upper side and laminate film 202 disposed on the lower side are sealed with a positive electrode and a negative electrode and an electrolyte therebetween. Wave shapes 203, which extend straightly in one direction and are arranged parallel to each other, are formed on surfaces of laminate films 201 and 202, respectively, such that flexibility of laminate films 201 and 202 is enhanced.
FIGS. 15A and 15B are views illustrating a manufacturing process of the thin pouch battery.
As illustrated in FIG. 15A, straight continuous wave shapes are formed in parallel at equal intervals on the laminate film of the thin pouch battery. Next, as illustrated in FIG. 15B, the laminate film is folded back with, bending position 206 as a base position and electrode group 207 including a positive electrode, a negative electrode, a separator, an electrolyte, or the like is inserted in the folded laminate film. Then, adhesion is performed on three sides except for the folded portion, and thus the thin pouch battery is obtained.